This invention relates to an accommodating case for accommodating and storing a tape cassette wound with a tape such as a magnetic tape without causing a shift in winding of the tape.
Conventionally, a tape cassette is handled wherein it is accommodated in an accommodating case in selling and storing it. As such a case, a case having a rectangular case main body for accommodating a magnetic tape cassette, provided with a lid at an engaging portion thereof capable of opening and closing, is employed. In the accommodating case, rotation-preventive pieces are protrudingly provided which are to be inserted into a winding shaft hole of a hub to prevent the shift in winding and the rotation of the hub by engaging the rotation-preventive pieces with hub claws.
Furthermore, since the rotation-preventive piece of a hub in the accommodating case, is in a planar form, in accommodating the tape cassette, the rotation of the hub is prevented by inserting the rotation-preventive piece between the hub claws. Therefore, the hub is often fixed in a state wherein it hangs and floats on the rotation-preventive piece. To avoid this, it is proposed to change the shape of a stopper piece (Japanese Examined Patent Publication 29820/1981 and Japanese Examined Patent Publication No. 31399/1982).
However, even when the rotation-preventive stopper piece is flexed in approximately a sideway chevron shape so that it does not touch the hub claw, the hub is shifted upwardly and does not dig into the hub claw, the rotation-preventive function thereof is not sufficient. When the rotation-preventive function thereof is sufficient, the upward shifting is conspicuous which deteriorates an appearance and grade thereof, and which is not satisfactory.
It is an object of the present invention to remove these conventional drawbacks and to provide a tape cassette accommodating case, wherein the opening and closing operation of the lid of the accommodating case is performed smoothly, the rotation-preventive function of the hub is promoted, the tape cassette can be accommodated and maintained safely in the accommodating case without causing the shift in winding of the tape, the handling of the tape cassette is simplified, the upward shifting is prevented, and which is excellent in the appearance and quality, the construction of which is simple and the cost of which is inexpensive.
According to an aspect of the present invention, there is provided a tape cassette accommodating case comprising:
a case main body forming an accommodating portion of a tape cassette;
a lid provided at said case main body capable of opening and closing; and
a pair of hub-rotation-preventive protrusions standingly provided at said lid;
said pair of hub-rotation-preventive protrusions each being composed of at least three stopper pieces radially provided to be inserted into a hub hole B;
a relationship between a radius r.sub.2 of said hub hole B and a radius r.sub.1 from the center of the hub hole B to a front end of a hub claw, and respective lengths of said stopper piece a, b and c, being c&lt;a.ltoreq.b, r.sub.1 .ltoreq.a&lt;r.sub.2, r.sub.1 &lt;b.ltoreq.r.sub.2 and c&lt;r.sub.1 ;
angles of .theta..sub.2, .theta..sub.3 and .theta..sub.1 made by said pieces a and b, b and c, and c and a being not multiples of 60.degree. C.;
wherein 120.degree.&lt;.theta..sub.2 &lt;180.degree. and .theta..sub.1 +.theta..sub.2 +.theta..sub.3 =360.degree..
When a magnetic tape cassette A is accommodated in the case main body 1 and the lid 3 is closed with a center of swiveling at an engaging portion 2, covering the magnetic tape cassette A, the pair of hub-rotation-preventive protrusions 9 are inserted into the hub holes B of the tape cassette A, thereby regulating and maintaining the position thereof.
In this case, even when the tape cassette shifts on the left hand side or on the right hand side in the case thereby moving the hub, one of the three stopper pieces of the hub-rotation-preventing protrusions 9 prevents the movement without digging into the hub claw. Moreover, at least one stopper piece is always put between the hub claws, thereby firmly preventing the rotation of the hub and smoothly performing the opening and closing operation of the lid.